Counter resetting mechanism



Nov. 7, 1967 T. H. BARKER ETAL COUNTER RESETTING MECHANISM original Filed Jan. 4, 1988 5 Sheets-Sheet 1 w m5. w c mmm W BN 5 W H.c R. A T R. J. W w S R v. m 8 W. W

Nov. 7, 1967 T. H. BARKER ETAL 3351278 GOUNTER RESETTING McHANIsM I original Filedaa. 4, 1983 5 sheets-sheet z Nov. 7,` 1967 T. H. BARKER ETAL COUNTER HESETTING MECHANISM i original Filed'Jan. 4, 1968 5 Sheets-Sheet 5 .NO' 7, 1967 I 'r. H. BARKER ETAL 3,351,278

COUNTER RESETTING MECHANISM Original Filed Jan. 4, 1963 5 Sheets-Sheet 4 Nov. 7, 1967 T. H. 'B'ARKER ETAL COUNTER RESETTING MECHANISM original Filed Jan. 4, 1988 REQUEST T/MER 5 shee'zs-sheet s 20 PPM GENERAro/a' 77 United States; Patent O 3,351,278 I COUNTER RESETTING MECHANISM Thomas H. Barker, Westerville, Ohio, and Robert C.

Nance, Wood-Ridge, and John R. Shine, Plainview, NJ., assignors to Bell Telephone Laboratories, Incorporated, New York, N.Y., a corporation of New York Original application Jan. 4, 1963, Ser. No. 249,512, now Patent No. 3,309,506, dated Mar. 14, 1967. Divided and this application Aug. 31, 1966, Ser. No. 604,079

Claims. (Cl. 235-144) This is a division of application Ser. No. 249,512, filed Ian. 4, 1963, now Patent No. 3,309,SO6.

This invention relates to electromechanical registers, and more particularly to so-called initial period timing registers which indicate the expiration of selectable time intervals.

It is frequently necessary for telephone operators to inform parties to a call that some predetermined period of time has elapsed, for example, the first three minute interval of the call. Since this period is actually a measure of the subscriber's taritf, it is: crucial that the timing operation be performed with utmost accuracy. In the past, it has been suggested that timers employing synchronous motors be used `for this purpose because of their characteristic accuracy and ruggedness. However, such devices have been found too costly to install in quantity, and the additional equipment which would be necessary to permit semiautomatic sharing of such timers among a group of operators would impose a prohibitive spa-ce requirement in already crowded telephone oifices. As a result, the usual method by which operators now perform initial period timing is by direct observation of a clock. Obviously, such a procedure is unduly burdensome whenan operator is called upon to timelseveral different calls concurrently.

Accordingly, one object of the invention is to decrease the size and complexity of electromechanical timers.

Another object of the invention'is to measure accurately periods of time on a selective basis.

Another object of the invention is Vto decrease the magnetic force required to reset a timer to its zero position.

Still another object of the invention is to indicate before timing commences whether or not a timer is functioning properly.

In accordance with the invention, a mechanism is provided comprising a primary cam and at least one secondary cam, the primary and secondary cams being mountedV for independent rotation on separate shafts. Means are provided for rotating the shaft bearing theprimary cam, which shaft is geared to the shaft of the secondary cams. A lobe on the primary cam actuates one set of contacts while lobes on each of the secondary cams actuate separate sets of contacts, the concurrent actuation of various combinations of the aforementioned contacts indicating the expiration of different periods of time.

One feature of the invention resides in a unique reset mechanism which returns the timer to its initial, or zero position with minimum power. In the embodiment of the invention described herein, the timing (primary and secondary) cams are disposed on coaxial shafts mounted for rotation on a single bracket. The bracket is mounted to be pivoted about a shaft under the control of a reset solenoid. Also pivotally mounted on the last-mentioned shaft is a mechanical claw. The `foregoing elements are so arranged that when the reset solenoid operates, the bracket and claw pivot toward each other simultaneously in a scissoring action. The shafts on which thetiming cams ride include heart-shaped cams which engage the claw during its travel and are rotated back to zero position.

' Another feature of the invention pertains to a test arrangement for determining before timing commences whether or not the timer is Operating properly. In one em- V3,35l,278 Patented Nov. 7, 1967 bodiment of this arrangement a test lobe projecting from one of the secondary cams and the lobe on the primary cam areshifted first into alignment and then out of alignm'entby test pulses which arerinitiated before the train of timed pulses commences. Followers riding the various cams sense this initial alignment and indicate that the cams are rotating properly.

The foregoing and' other objects and features of the invention will be more thoroughly understood by reference to the following detailed description of an illustrative embodiment of the invention in conjunction with the accompanying drawing of which:

FIGS. 1 and 2, respectively, are a perspective view, partially cut away, and an elevation view of an electromechanicaltiming register embodying the invention;

FIGS. 3 and 4 are sectional views illustrating the operation of the reset mechanism;

FIG. 5 is an isolated view of the single-slotted disc forming a part of the reduction gear mechanism;

FIGS. 6, 7 and 8 are sectional views illustrating the operation of the reduction gear mechanism;

structure embodying the invention is shown comprising an` es'sentially U-shaped lbracket 1 which serves as a frame upon which the entire timing mechanism is mounted. Bridged across the jaw of bracket 1 is a transverse strut 2, upon which is mounted by conventional threaded fasten- -ers 3, four separate contact pileups comprising electrical contacts 4 separated by insulated spacing bars 5.. The actuation of contacts 4 is governed by individual follower rods 6 through 9 which respectively ride along the rims of timing cams 10 through 13, respectively. The various contacts 4 form switches of a logic circuit, shown symbolically in and explained below in connection with FIG.

V10,'which recognizes when selected time intervals have expire'd.

Each of cams 10 through 13 has at least one raised timing lobe along its rim which lifts one of the followers 6 through 9, and thereby actuates the various switches formed by electrical contacts 4. One of the cams, cam 13` in the embodiment of the invention described herein, comprises an extra lobe which is used for test purposes to determine whether or not the timer is functioning properly before timing commences. The lobes on the various cams are disposed in fixed rotational position with respect to each other such that at the termination ofV successive pre-determined time intervals, different combinations of followers 6 through 9 will be lifted by their respective lobes.

The timing cams are mounted on a pair of coaxial shafts 14 and 23, the outer ends of which are journaled through opposite parallel side flanges 16 and 17 of a U- shapedV yoke.15. At their abutting ends, shafts 14 and 23 are fastened together, forexample by a common coaxial i 15 is mounted for rotational, or pivotal, move-` ment about a shaft 22 which, as shown, is passed through side fianges 16 and 17 of yoke parallel to 'but rearwardly displaced from -shafts 14 and 23. Shaft 22, in turn, is journaled through bearing apert-ures 24 and 25 which are bored on opposite sides of bracket 1.

Mounted for rotation on shaft 14 is a driven gear 26 from which shaft 14 receives its motive power, timing cam 10, single slotted disc 27 which forms the input elernent of a reduction gear mechanism, and heart-shaped cam 28 used to reset shaft 14 to an initial position. Similarly mounted on the shaft 23 is a heart-shaped cam 29 used to reset shaft 23 to an initial position, an output gear 30 of the reduction gear mechanism from which shaft 23 receives its motive power, and timing cams 11, 12 and 13. The reduction gear mechanism, which will be explained in detail below, rotates shaft 23 only a single angular step for one complete 360 degree rotation of shaft 14. The aforernentioned elements mounted on shafts 14 and 23 are retained in their relative axial positions by conventional spacer rings 31.

A second pair of coaxial shafts 34 and 37 are mounted parallel to shafts 14 and 23. The outer ends of shafts 34 and 37 are jo-urnaled through bearing apertures 32 and 33, which are 'bored in opposite sides of bracket 1, and their inner, or abutting, ends are connected for independent rotation in the same manner as shafts 14 and 23. Mounted on shaft 34 are the elements for supplying the driving power to shaft 14, comprising ratchet wheel 35 and driving gear 36 which is axially positioned to engage gear 26 of shaft 14. Mounted on shaft 37 is the intermediate gear 39 of the aforementioned reduction gear system of which slotted disc 27 is the input, or driving element, and gear 30 is the output, or driven element. As shown, intermediate gear 39 comprises a plurality of radially projecting teeth of which a first alternate set extends Vaxially across the entire width of the gear, and a second alternate set extends only partially across the width of the gear. A resilient finger 52 extending forwardly in cantilever fashion from strut 2, angles downwardly near its free end to engage only those teeth which extend across the entire width of gear 39. Finger 52 prevents overshoot while also allowing gear 39 to be rotated by disc 27.

Ratchet wheel 35 is driven by a pawl 40 which is pivotally fastened to armature 41. As shown, armature 41 comprises a flat face 42 terminating on either side by perpendicularly rising side flanges 43 and 44. Flanges 43 and 44, have bearing apertures located approximately midway along their lengths through which a shaft 48 is passed in order that face 42 may be rotated with respect to core 45 of a timing solenoid 46. Solenoid 46 is disposed on frame 1 lbetween a pair of walls 49 and 50 (shown in FIG. 2) which extend forward of core 45 to provide a mounting for shaft 48 parallel to shafts 14 and 23. The lower end of side fiange 43 comprises an extension 47, to the outward tip of which pawl 40 is pivotally connected. A return spring 51 has one end connected to extension 47 in the vicinity of pawl 40, and its other end connected to a cantilever (not shown) parallel to cantilever 21 but displaced therefrom along strut 2. Hence when timing solenoid 46v is energized, face 42 is pulled toward core 45, causing pawl 40 to engage ratchet wheel 35 and thus advance shaft 34 in steplike fashion. When timing solenoid 46 is de-energized, tensioned spring 51 returns armature 41 to its original position disengaged from core 45.

The invention accomplishes timing by counting the number of accurately spaced pulses which are applied by a standard to energized timing solenoid 46, and the expiration of selected time intervals is recognized by sensing with the logic circuitry of FIG. 10 the actuation by cams 10 through 13 of particular combinations of contacts 4. FIG. 9 shows the relative rotational positions to which timing cams 10 through 13 are reset before timing is commenced. It will be noted that at reset position each of the follower rods' 6 through 9 rests upon the rim of its associated cams 10 through 13, none of the rods being lifted at this time. Each of the cams has a single timing lobe, and cam 13, in addition to its timing lobe, comprises a test lobe 53 which is approximately one-half the width of a timing lobe. The timing lobes of cams 11, 12 and 13, lobes 54, 55 and 56 respectively, are rotationally disposed from each other in fixed relation, these cams all being mounted upon shaft 23. Cam 10, however, is mounted on shaft 14, and consequently its timing lobe 57 changes in rotational position with respect to the other timing lobes.

In telephone central offices it is usual to have available a pulse source, or standard, which emits 20 periodic pulses per minute, that is, one pulse every three seconds. Consequently, it is convenient in timing telephone calls that ratchet wheel 35 and gears 36 and 26 each consist of twenty teeth so that shaft 14, and hence cam 10, completes a single revolution each minute. Since the reduction gear mechanism comprising single-slotted disc 27 and gears 39 and 30 is constructed such that shaft 23 is rotated one angular step per each complete revolution of shaft 14, as will be explained in detail immediately below, the invention facilitates timing of discrete intervals in multiples of one minute.

FIGS. 5 through 8 illustrate the operation of the reduction gear mechanism to rotate shaft 23 one step for each complete revolution of shaft 14. As illustrated in FIG. 5, single-slotted disc 27 comprises an outer plate 58 and an adjacent coaxial inner plate 59 of smaller diameter. Accordingly, the rim of inner plate 59 provides a shoulder 60 upon which ride only those teeth that extend partially across gear 39. Shoulder 60 is interrupted by a pair of posts which form a slot extending through outer plate 58. The teeth which extend entirely across gear 39 ride along the rim of outer plate 58, as is best shown in FIG. 1.

It is seen from FIG. 6 that disc 27, which is rotationally stepped in the direction of the arrow by shaft 14, will exert no motive force on gear 39 until the disc reaches the position shown in FIG. 7. At this time tooth 63, which extends only partially across gear 39 engages post 62. As disc 27 is further rotationally stepped, gear 39 is rotated in such manner that tooth 64, which extends entirely across gear 39, is meshed into the single slot of the disc as shown in FIG. 8. As disc 27 is still further rotated, tooth 64 engages post 61 (the rear wall of the slot) and rotates gear 39 such that tooth 66 now rides shoulder 60 and teeth 64 and 65 ride the rim of outer plate 58. Disc 27 may now 'be rotated without also rotating gear 39 until the position of PIG. 7 is once again reached. It will be observed that each step of gear 39 (corresponding to one complete revolution of disc 27) comprises two successive incremental rotational movements, the first occurring when a tooth is meshed into the single slot and the second occurring when the tooth is expelled from the slot.

The control circuitry which governs the operation of the timer, and which includes the logic circuitry for recognizing the expiration of the selected intervals, is shown schematically in FIG. 10. For those not familiar with the detached contact symbolism used in the drawing, crosses (X) and bars through conductors represent different types of bistate switches, or more accurately, the condition of a particular bistate switch when actuated. A cross through a conductor, hereinafter referred to as a set of make contacts, represents a switch which exhibits a short circuit characteristic when actuated, but exhibits an open circuit characteristic at all other times. Conversely, a bar through a conductor, hereinafter referred to as a set of break contacts, symbolizes a switch which presents an open circuit characteristic when actuated but presents a short circuit characteristic at all other times. For purposes of simplicity, the various sets of make and reak contacts are labeled according to the elements by which they are actuated. For example, if a particular VES set of make contacts is actuated by the lifting of follower rod 6, this set is designated 6 with a subscript to distinguish between the various contacts operated by the same follower rod.

In describing the operation of the invention, let it be assumed that cams through 13 are initially in rotational positions identical to those shown inV FIG. 9, and that single-slotted disc 27 and gear 39 are in the relative positions shown in FIG. 7. The manner by which the for'egoing elements are set to these respective positions will be described below in connection with the reset mechanism. v

With reference to FIGS. 10 and 11, the operator first manpulates the selector switch of FIG. 11 to the position corresponding to the interval desired to be timed. The encircled numerals in FIG. 11 are in correspondence with the encircled numerals'rin FIG. 10, and serve to indicate the manner in whichl selector switch 68 is physically interconnected in the' circuit. As shown, if three minutes is the desired interval, the switch handle 74 is thrown upwardly, thereby closing make contacts 68a but leaving closed break contacts 68s undisturbed. Accordingly, a vpath is prepared through make contacts 68a and break contacts 68a through which' lamp 92 may be flashed by pulse generator 73 when relay 69 is operated'and followers 6 and 7 are lifted. When the switch 68 resides in the position pictured in FIG. 11, e.g., the four minute position, a path is provided via closed break contacts 68h and 68a through which lamp 92 may be flashed when relay 69 is operated and followers 6 and 8 are lifted. Similarly, when it is desired to time a five minute interval, handle 74 is thrown downwardly which prepares a path via make contacts 68a? through which lamp 92 is flashed when relay 69 is operated and followers 6 and 9 are lifted. It is obvious from the foregoing that expiration of selectable time intervals are recognized by the concurrent lifting of combinations of the various follower rods on their respective timing lobes.

As labeled in PIG. 11, the timer is capable of timing one of several selectable intervals. In the embodiment of the invention described herein, three distinct intervals may be selected, a three minute interval associated with cam 11, a four minute interval associated with cam 12, and Va five minute interval associated with cam 13. As the description proceeds, however, it will become apparent to one skilled in the art that the particular configuration described herein is easily modified to select other time intervals by varying the relative rotational positions of cams 11, 12 and 13, and that each of these cams, by the inclusion of additional timing lobes, may provide a selection of more than one timed interval.

According to the invention, the operator is able to deterinine whether the time is functioning properly before timing is commenced by momenta'rily depressing a nonlooking Request for Timing key 67 (PIG. 10) and observing whether lamp 92 lights. More specifically, When key 67 is depressed, solenoid 46 is energized through an obvious path to ground Accordingly, armature 41 is drawn toward core 45, which brings pawl 40 into engage-:

ment with ratchet Wheel 35 so as to rotate gear 36 1/20 of a revolution. Concomitantly, gear 26, which is meshed wit'h gear 36 is rotated a corresponding I1/20 of a revolution along with cam 10 `and a single-slotted disc 27 'which are all mounted on shaft 14. Thus, follower rod 6 is lifted by timing lobe 57 of cam 10', which actuates the associated electrical contacts 4 which form switches 6a through 6c of FIG. 10.

Since single-slotted disc 27 and gear 39 are in the relative position shown in FIG. 7, the rotation of shaft 14 at this time causes gear 39 to berotated to the position shown in PIG. 8. In response, gear 30V is correspondingly rotated by gear 39, `as are cams 11 through 13 which are mounted on shaft 23 along VwithV gear 30. It will be noted, however, that the aforementioned rotation of gear 30 and cams 11 through 13 are only the first ineremental of potential. Thus, by observing that lamp 92 has been energized, the operator is aware that shafts 14, 23, 34 and 37, and the elements mountedV thereon, are all rotating properly in response to the application`V of pulses to timing solenoid 46. Since the foregoing occurs before timing is commenced, such apparatus may be considered to constitute a test circuit for checking the timerprior to actual service.

A'fter the interval desired to be timed has been selected by appropriate manipulation of switch 68, and the time! has been found to be functioning properly, timing is commenced by momentarily depressing the nonlocking Start Timing key 72. Since at this time followers 6 and 9 are lifted, relay 69 is opera'ted through a path comprising ground, the wincling of relay 69, break contacts 69, conductor 75, key 72, break contacts 69a, make contacts 9a and 6a, break contacts 69b, conductor 71 and a positive source of potential. When relay 69 operates, its associated switches 69a through 698 are operated, which results initially in relay 69 being locked up through an obvious path including make contacts 698. The positive source of potential applied to energize relay 69 is prevented from also energizing solenoid 46 by break contacts 69 which now present an open circuit. Break contacts 69b open to solate the positive potential on conductor 71 from the filament of lamp 92, and make contacts 69a close to prepare a path through which pulse generator 73 energizes lamp 92 when the appropriate combination of follower rods is lifted. Make contacts 69d are closed to provide a path through which timing pulses from the standard 77, a 20 pulse per minute generator, are applied to energize timing soleno'id 46. v

It will be recalled that when the operator depressed Request for Timer key 67, single-slotted disc 27 and gear 39 Were shifted to the relative position shown in FIG. 8, which resulted in cams 11 through 13 being rotatedV through the first incremental movement of a rotational step. When the operator depresses key 72, the same momentary pulse applied to operate relay 69, as aforementioned, is `also applied through conductor 75 and diode 76 to the winding of timing solenoid 46. This pulse imparts the second incremental movement to cams-11 through 13' and thus completes a rotational step of these cams. In this second incremental step tooth 64 is expelled from the slot in disc 27 to a positionwhere it will now ride on the rim of outer plate 58. Consequently, disc 27 is now free to rotate Without further rotating gear 39 until the position shown in FIG. 7 is once again resumed. Test lobe 53 Vof cam 13 (FIG. 9) is cut sufliciently narrow so that follower rod 9 completely traverses test lobe 53 after the aforementioned second incremental movement has been completed. All of the foregoing occurs before the first timing pulse from generator 77 is applied to energize solenoid 46.

The first pulse from generator 77 which energizes timing solenoid 46 marks the beginning of the timing inter- Val, and therefore represents time zero. This first timing pulse draws armature 41 toward core 45, which in turn rotates cam 10 through 1/20 of a revolution. Cams 11 through 13 are stationary at this time since disc 27 and gear 39 are in relative position similar to that of FIG. 6,

i.e., the teeth of gear 39 vare not in engagement with post a' slotted disc 27 will be rotated back to the position of FIG. 9 fifty-one seconds (seventeen pulses of standard 77) after the time zero pulse. On the twenty-first pulse, or fiftyfour seconds after time zero, follower' 6 is once again lifted by lobe '7 of cam 10. At the same time, gear 39, and hence cams 11 through 13 are rotated through the first incremental movement of their second rotational step. At this time, however, as will be observed from FIG. 9, none of follower rods 7 through 9 will as yet have engaged their respective timing lobes 54 through 56. Consequently, make contacts 7a, 8a and 9a -remain unact-uated, not permitting flashing pulses from generator 73 to energize lamp 92.

One minute 01' twenty pulses later, follower 6 will again Ieside on index mark 1 of cam 10, and follower rods 7 through 9, relatively speaking, will have advanced their first incremental movement toward index mark 3 on cams 11 through 13. At this time one minute and fifty-four seconds have elapsed since time zero. Twenty pulses later, that is to say, after two minutes and fifty-four seconds have elapsed from time zero, the first incremental movement of cams 11 through 13 will bring follower rod 7 into engagement With timing lobe 54, thereby actuating make contacts 7a. As before, follower rod 6 will be in engagement with lobe 57 of cam so that make contacts 6a are actuated. Furthermore, if the operator has selected a three minute nterval to be timed, a path |will be established, as aforementioned, through switch 68. Accordingly, flashing pulses are applied to lamp 92 through make contacts 69c, 6a, '7a and 68a, break contacts 68a and conductor 70. Thus, lamp 92 commences to flash t'wo minutes and ifty-four seconds after timing was commenced, thereby warning the operator that the initial three minute period of the telephone call is about to expire in six seconds.

lt has been found expedient in telephone practice to allow lamp 92 to remain fiashing for a short period of time, e.g., 12 seconds, after the initial period has expired, and then to energize the lamp steadily to serve as a reminder, in case the operator was otherwise occupied during the fiashing interval that such initial period has expired. Consequently, timing lobe 57 extends rearwardly for a spacing of four index marks or 12 seconds, after time zero. When follower rod 6 returns to the rim of cam 10, the path connecting generator 73 to lamp 92 is broken by make contacts 6a, but simultaneously a path is established for applying steady potential to lamp 92 through make contacts 69a, conductor 78, break contacts 6b, make contacts 7a and 68a, break contacts 68c and conductor 70. It will be observed that if cams 10 through 13 were allowed to con-- tinue revolving, follower rod 7 will eventually return to the rim of cam 11, which would open the previously described path energizing lamp 92 steadily. However, when follower 6 returns to the rim of cam 10 three minutes and twelve seconds after time zero, the steady potential applied to energized lamp 92 is also applied through break contacts 6c, conductor 75 and diode 76 to maintain timing solenoid 46 steadily operated, in effect overriding the pulsing action of standard 77. Thereafter, the rotating elements of the timing mechanism remain at rest until the operator restores the mechanism and associated circuitry to their initial condition and once again depresses key 67.

It should be obvious without further detailed explanation that initial periods of four minutes and five minutes (or in the embodiment described herein four and five minutes minus six seconds) may be selectively timed by positioning nob 74 of the selector switch (FIG. 11) to the appropriate position indicated. For example, twenty pulses, or one minute, after timing lobe 54 of cam 11 has lifted follower 7, timing lobe 55 is rotated so as to lift follower 8. Concurrently, timing lobe 57 of cam 10 is rotated so as to once again lift follower 6. With the selector switch of FIG. ll positioned as shown in the drawing, break contacts 68h and 68a present short circiut paths across their terminals, and consequently a path is established through make contacts 690, 6a and 8a, break contacts 6817 and 68a, and conductor 78 for allowing generator 7 3 to flash lamp 92. On the fourth pulse, or 12 seconds, after the four minute period has expired, follower 6 once again returns to the rim of cam 10, thereby establishing dual paths for energizing lamp 92 steadily and maintaining solenoid 46 constantly energized.

If the selector of FIG. 11 were thrown downwardly to the five minute mark, the same sequence of events as described would occur four minutes and fifty-four seconds after time zero, except that flashing voltage would be applied through make contacts 9a and 68d rather than through make contacts 8a and break contacts 6817 and 68a. It should be equally clear that without deviating from the principles of the invention other intervals can be timed by either changing the relative rotational positions of cams 11, 12 and 13, or by mounting additional cams on shaft 23 and correspondingly adding to the logic circuitry of FIG. 10, or by adding timing lobes to the existing cams 11, 12, and 13 and substituting a selector switch with more possible combinations of make and break contacts than the selector switch of FIG. 11.

Another unique feature of the invention resides in the reset mechanism by means of which shafts 14 and 23, and their associated cams and gears, are brought back to the initial position shown in FIGS. 7 and 9. As shown in FIG. 2, a reset solenoid 80 is mounted within the walls of frame 1 to the right of and slightly below timing solenoid 46. A reset armature 81, shown in detail in FIGS. 3 and 4, is pivotally mounted on a shaft 82 which is journaled through the right wall of frame 1 and a second wall 83 (FIG. 2) whi-ch is disposed to the left of solenoid 80. An arm 84 extends upwardly from armature 81, terminating in a roller 85, and a finger 91 also extends upwardly substantially parallel to arm 84. As is best illustrated in FIG. l, roller 85 rides upon a shelf 86 which extends perpendicularly inward from the tip of flange 17.

Mounted on shaft 22, about which yoke 15 rotates, is a mechanical claw 87. The claw is axially disposed along shaft 22 so that its curled tip 88 may be rotated to engage the rims of heart-shaped cams 28 and 29. A tab 89 extends downwardly from claw 87 in an engageable position with respect to the inner surface of finger 91.

To operate the reset mechanism solenoid 80 is energized by depressing '*Reset key 79 (FIG. 10). Before key 79 is depressed shafts 14 and 34 are relatively positioned as shown in FIGS. l and 3, that is to say, with gears 26 and 30 in respective engagement with gears 36 and 39. When solenoid 80 is energized, armature 81 pivots around shaft 82, thereby pulling arm 84 and finger 91 toward core 90. As a result, roller 85 rides along shelf 86, forcing yoke 15 to pivot around shaft 22 in the direction shown by the arrow (FIG. 4). As yoke 15 pivots, gears 26 and 38 are respectively disenga'ged from gears 36 and 39, thereby rendering shafts 14, 23, 34- and 37 free to rotate. At the same time, the inner surface of finger 91 engages tab 89 which pivots claw 87 about shaft 22. Consequently, curled tip 88 of claw 87 engages the rims of heart-shaped cams 28 and 29 and forces these cams to the position shown in PIG. 4. Accordingly, cams 10, 11, 12 and 13, gear 26, single-slotted disc 27 and gear 30 are rotated to relative angular positions as determined by the angular position of the heart-shaped cams. Also, gear 39 is rotated to the proper angular position by the downwardly projecting tip of resilient finger 52. It will be seen, therefore, that if heart-shaped cams 28 and 29 are in proper angular position with respect to the remaining elements on shafts 14 and 23, single-slotted disc 27 and gear 39 will be positioned as shown in FIG. 7, and cams 10 through 13 will be positioned as shown in FIG. 9, when reset key 79 is depressed. When reset key 79 is released, spring 20, which was placed in tension by tab 19 when yoke 15 was pivoted about shaft 22, exerts a restoring force which repivots the yoke back to its original position in which the gears on shafts 14 and 23 once 9 again reside in engagement with the correspondin'g gears on shafts 34 and 37.

It is highly desirable that the reset mechanism return the various cams and gears to the reset position in as short a time as possible. If there were excess delay in this operation, the various gears and ca-ms might not entirely be reset when key 79 is released. In such a case arm-ature 81 would be released from core 90, and the various :gears would return to mutual en-ga'gement with cams 10 through 13 out of proper rotational ali'gnment. It is a well-known princi'ple that the magnetic attraction between two objects varies in inverse proportion to the square of the distance separating them. The reset mechanism of the present invention utilizes this principle to distinct advantage by causing the heart-shaped cams 28 and 29 and the curled tip of claw 87 to approach each other in a '*scissoring motion during reset.

In order for the various ,gears and cams to be reset to the rotational position shown in FIG. 4, it is necessary for arm 84 to be rotated suficiently about its shaft 82 such that the curled tip 88 of the claw 87 is brought into en- 'gagement with the crevice of the heart-shaped cams. In

. accordance with the present invention, as armature 81 is drawn toward core 90, thereby urgin-g yoke 15 to displace the heart-shaped cams toward claw 87, tip 88 is simultaneously pivoted toward the heart-shaped cams. Consequently, the arc through which armature 81 must be pivoted in order for claw 87 and the heart-shaped cams to be brought into the engaged position shown in FIG. 4 is substantially decreased. Since al smaller rotational Inovement is required of armature 81 thanwould otherwise be required if tip 88 of claw 87 were stationary, armature 81 may be initially disposed in closer proximity to core 90, and hence experiences a proportionately greater magnetic pull.

Althou'gh only a single embodi'ment of the invention has been described herein, it should be obvious to one skilled in vthe art that various other modifications and adaptations may be designed without deviating from the spirit and scope of the invention.

What is claimed is:

1. In a register having a rotatable shaft, apparatus for setting said shaft to a predetermined rotational orientation comprising, in combination, a bracket -mountin'g said shaft for rotation, an eccentric element fixedly mounted on said shaft, a claw element, means for pivoting said bracket towa-rd said claw element and said claw element toward said bracket concurrently in a scissoring motion, said claw being positioned to engage said eccentric element during at least a portion of sai-d motion.

2. Apparatus in accordance with claim 1 wherein said eccentric element comprises a heart-shaped cam.

3. In a register having a rotatable shaft, apparatus for setting said rotatable shaft to a predetermined rotational orientation comprising, in combination, a bracket mountin'g said rotatable shaft for rotation, a heart-shaped cam fixedly mounted on said rotatable shaft, a second shaft, said bracket bein'g pivotally mounted on said second shaft, a claw element pivotally mounted on said second shaft, means for pivoting said bracket 'and said claw element toward each other concurrently about said second shaft in a scissoring motion, said claw 'element being axially positioned on said second shaft for engagement with said heart-shaped cam during at least part of said motion.

4. In a register having a rotatable shaft, apparat'us for setting said rotatable shaft to a predetermined rotational orientation comprising, in combination, a bracket mountin'g said rotatable shaft for rotation, a heart-shaped cam fixedly mounted on said rotatable shaft, a second shaft, said bracket being mounted for pivot'al motion about said second shaft, a claw element 'pivotally mounted on said second shaft, means including a solenoid for pivoting said bracket about said second shaft toward said claw element, bearin'g means included both in said bracket and said claw element for pivoting said claw element toward said bracket when said bracket is being 'pivoted toward said claw element, whereby said bracket and said claw element execute a scissoring motion, and said claw element being aXially positioned on said second shaft to engage said heart-shaped cam during at least a portion of said scissoring motion.

5. Apparatus in accordance with claim '4 wherein said bearing means included in said bracket compris'es a finger, said bearng means in said claw element comprises a tab, and said finger is positioned to en'gage said tab when said bracket is pivoted, thereby pivotin'g said claw element.

References Cited UNITED STATES PATENTS 2,219,636 10/ 1940 Schwartz 235-144 2,769,596- 11/ 1956` oosli 235 14'4 '3,05 3,441 9/19'62 Vroom l-- 235-144 3,064,893 11/1962 Grinstead 235-144 3,l22,3 15 2/ 1964 `Krebsdzlo 235-144 RICHA'RD B. WILKINSON, Primary Examner. S. A. WAL, Assistant Examiner. 

3. IN A REGISTER HAVING A ROTATABLE SHAFT, APPARATUS FOR SETTING SAID ROTATABLE SHAFT TO A PREDETERMINED ROTATIONAL ORIENTATION COMPRISING, IN COMBINATION, A BRACKET MOUNTING SAID ROTATABLE SHAFT FOR ROTATION, A HEART-SHAPED CAM FIXEDLY MOUNTED ON SAID ROTATABLE SHAFT, A SECOND SHAFT, SAID BRACKET BEING PIVOTALLY MOUNTED ON SAID SECOND SHAFT, A CLAW ELEMEMT PIVOTALLY MOUNTED ON SAID SECOND SHAFT, MEANS FOR PIVOTING SAID BRACKET AND SAID CLAW ELEMENT TOWARD EACH OTHER CONCURRENTLY ABOUT SAID SECOND SHAFT IN A SCISSORING MOTION, SAID CLAW ELEMENT BEING AXIALLY POSITIONED ON SAID SECOND SHAFT FOR ENGAGEMENT WITH SAID HEART-SHAPED CAM DURING AT LEAST PART OF SAID MOTION. 